Atoms and Periodic Table Chem Test 88%
Who was the first to propose the existence of atoms?
(B) Democritus
A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?
(B) Na
How many valence electrons does aluminum (Al) have available for bonding?
(C) 3
Which characteristic is given by the angular momentum quantum number?
(C) orbital shape
Which is a correct set of values of m for one of the subshells of n = 2?
(A) -1, 0, 1
Which statement best describes how electrons fill orbitals in the periodic table?
(A) Electrons fill orbitals in order of their increasing energy from left to right.
The diagram below shows some subatomic particles.Which of these statements best identifies the particle that is labeled with an X?
(A) It is either a nucleus or a proton.
Which scientist is known for developing the planetary model of the atom?
(A) Niels Bohr
Which element is classified as an alkali metal?
(A) Rb
Among the elements of the main group, the general trend in the first ionization energy moving across a period is not followed between group 2 and group 13. Which best explains these exceptions?
(A) The ionization energy decreases because the full s orbital shields the electron entering the p orbital.
Which element is the most reactive?
(A) sodium
Which set of numbers gives the correct possible values of l for n = 2?
(B) 0,1
What is the atomic number of zirconium?
(B) 40
Which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the 5s subshell?
(B) Kr
Iron, an element with the chemical symbol Fe, is an important element. It is used to make steel and is part of the substance that transports oxygen throughout the human body.Which statement about Fe is supported by the modern atomic theory but not John Dalton's theory?
(B) The electrons of iron have probable locations in a region of space around the nucleus.
Which of Dalton's ideas about the atom did J.J. Thomson's experiment disprove?
(C) It disproved that atoms contain protons.
Which describes Ernest Rutherford's experiment?
(C) Positive particles are fired at gold foil. Most pass through, but some bounce back.
Hydrogen has three isotopes 1H, 2H, and 3H. What is the difference between these three isotopes?
(C) The number of neutrons ranges from 0 to 2.
In which orbitals would the valence electrons for selenium (Se) be placed?
(C) s orbital and p orbital
Which best explains why ionization energy tends to decrease from the top to the bottom of a group?
(D) Electrons get farther from the nucleus.
What did Ernest Rutherford's gold foil experiment demonstrate about an atom?
(D) Positive charge occupies a very small volume in the atom.
Which element has the largest atomic radius?
(D) Sb
How did Niels Bohr describe electrons in his atomic model?
(D) They orbit the central nucleus in discrete paths.
When electrons are removed from the outermost shell of a calcium atom, the atom becomes
(D) a cation that has a smaller radius than the atom.
To show the electron configuration for an atom, when would it be better to use an orbital notation than to use a written configuration with numbers, letters, and superscripts?
(D) when the aim is to show electron distributions in shells
